In the type of optical printer noted above, generally, the toner transferred to the copying paper in an electrophotographic process is maintained in an unfixed condition until the copying paper reaches a fixing device. In order to avoid the necessity of providing a special means for toner adhesion, the recording paper is transported to the fixing device with the recorded side facing up. The recording paper is discharged in the same face up state after the fixing process. The recording paper thus discharged is stacked with new sheets successively overlying preceding sheets.
According to this arrangement, however, when recording information spanning a plurality of pages is recorded on separate sheets of recording paper, new sheets are successively placed on preceding sheets with their recorded sides facing up. With a machine constructed to start recording the first page of documents, the order of the pages becomes reverse of the proper order of to recorded information. This requires a manual operation after a recording operation for rearranging the sheets to put the pages in an ascending order from top to bottom.
This rearranging operation is increasingly troublesome as the number of pages of recorded information increases. There are recording apparatus having means for dispensing with the manual rearrangement. One type of such apparatus includes a reversing device for discharging recording paper face down after a recording operation, thus in the order of the page numbering. The other type includes a memory for storing an entire piece of input recording information spanning a plurality of pages, and starts recording the part of the information corresponding to the final page. With the second type of apparatus, therefore, recording paper is discharged face down already in the order of the page numbering.
The above known apparatus have the following problems.
In the apparatus including the paper reversing device, this device occupies a large space for turning over the recording paper. As a result, the apparatus must have a large overall construction, particularly if the reversing device is provided in addition to an existing paper face-up discharge device. With a printer which simply records input information, compactness may be possible to some extent with an arrangement for stacking recording paper discharged after being reversed by the reversing device on a tray or the like mounted on a top surface of the printer. However, with a recording apparatus having both a digital function for recording input recording information dot by dot and an analog function for copying documents (which has been used increasingly in recent years and is often called a digital-analog copier), such a discharge arrangement cannot be employed since a document table is provided on the top surface of the apparatus. It is especially difficult to provide the latter apparatus with the paper reversing device without incurring the problem relating to space.
Regarding the apparatus including a memory for storing information spanning a plurality of pages to start printing the final page, the number of pages of recording information constituting one document is variable and sometimes exceeds one hundred. This means that, in order to realize the page arrangement, a large capacity memory is required to meet the rare recording conditions in which information is recorded on a great number of pages. Such a construction has no advantage from the point of view of cost performance.
The conventional recording apparatus also have the following problems when recording information on both sides of recording paper.
When recording image information spanning a plurality of pages on both faces of recording paper, i.e. duplex recording, the recording paper is fed from a paper supply section for recording an image on a front side thereof, and thereafter redirected for image formation on a reverse side thereof prior to discharge. In contrast with a simplex recording mode in which image are successively recorded on one side of recording paper supplied sheet after sheet, the duplex recording mode is interrupted by standby periods each occurring during a reversing operation required between image formation on the front side of one sheet and image formation on the reverse side thereof. Since such a standby period takes place with each sheet of copying paper, the entire recording operation is time-consuming.